including components under the GPL (e.g., Linux, BusyBox) and components

under the LGPL (e.g., the GNU C Library).  Sometimes, these programs have

been patched or slightly improved by direct modification of their sources,

companies often distribute fully independent, proprietary programs,

developed from scratch, which are designed to run on the Free Software operating

system but do not combine with, link to, modify, derive from, or otherwise

In the latter case, where the work is unquestionably a separate work of

creative expression, no copyleft provisions are invoked.

The core compliance issue faced, thus, in such a situation, is not an discussion of what is or is not a

conveyance of binary works based on GPL'd source, but without Complete,

Corresponding Source.  This tutorial therefore focuses primarily on that issue.

Admittedly, a tiny

situations are so rare, and the details from situation to situation differ

greatly.  Thus, such situations require a highly

fact-dependent analysis and cannot be addressed in a general-purpose

professionally and noticed clear similarities to FSF's GNU GCC\@. FSF's

Compliance Engineer asked the reporters to run standard tests to confirm

the violation, and it was confirmed that Bortez's SDK was indeed a

of features, including support for a specific consumer device chipset and

additional features to aid in the linking process (``LP'') for those

specific devices. FSF explained the rights that the GPL afforded these

FSF brought the matter to the attention of Bortez, who immediately

escalated the matter to their attorneys. After a long negotiation,

GCC\@. Bortez released most of the source, but some disagreement

FSF inquiries, Bortez reaudited the source to discover that FSF's

analysis was correct. Bortez determined that LP included a number of

source files copied from the GCC code-base.

  cannot effectively replace them.

  Such an outcome is simply further evidence that the combined work in

  If the other components cannot stand on their own and be useful without

  the GPL'd portions, then one cannot effectively argue that the work as a

\item {\bf The whole product is not always covered.}  In this case,

  Vigorien had additional works aggregated. The backup system was a suite

  of utilities, some of which were the GPL and some of which were not. While

  the cryptographic routines were tightly coupled with GNU tar and clearly

  independent works merely aggregated with the distribution of the

  GNU-tar-based product.

  the GPL are ignored. If companies do not want to release source code

  for some reason, then they should not base the work on GPL'd software.

  No external argument for noncompliance can hold weight if the work as

  The ``security concerns'' argument is often floated as a reason to keep

  software proprietary, but the computer security community has on

contains a software-programmable radio transmitter, regulations in (at

least) the USA and Japan prohibit release of those portions of the code

that operate the device. Since this is a low-level programming issue, the

Linux.  A decade later, this situation remains largely unresolved.

\section{Lessons Learned}

because it clears up a common misconception about the GPL\@.

The GPL is often mistakenly criticized because it fails to give a

\section{GPLv2~\S1: Verbatim Copying}

\label{GPLv2s1}

can be a source of great confusion when not properly understood.

In considering GPLv2~\S2(b), first note the qualifier: it \textit{only} applies to

education efforts on this matter, many still believe that modifiers

of GPL'd software \textit{must} publish or otherwise

share their changes.  On the contrary, GPLv2~\S2(b) {\bf does not apply if} the

\begin{quote}

``...that in whole or part contains or is derived from the Program or any part thereof.''

\end{quote}

derived from'' the GPL'd software, then the requirements of GPLv2~\S2(b)

apply.  The GPL invokes its control as a copyright license over the

modification of the work in combination with its control over distribution

of the work.

\begin{quote}

[The work must] be licensed as a whole at no charge to all third parties

under the terms of this License.

programmer is indeed the copyright holder of those new changes.  However,

those changes are part and parcel to the original work distributed to

the programmer under GPL\@. Thus, the license of the original work

% {\cal I}

\newcommand{\gplusi}{$\mathcal{G\!\!+\!\!I}$}

\gplusi{} without paying them a hefty sum?)  The license of \workg{}, the

GPL, states the  options for the copyright holder of \worki{}

who may want to create and distribute \gplusi{}. The  GPL's pre-granted

of the GPL are upheld, goes far above and beyond the permissions that one

would get with a typical work not covered by a copyleft license.  (Thus, to

say that this condition is any way unreasonable is simply ludicrous.)

that.  Instead, it says that the licensing under terms of the GPL must

extend to anyone who might, through the distribution chain, receive a copy

of the software.  Distribution to all third parties is not mandated here,

a way that extends to all third parties who may ultimately receive a

copy of the software.

In summary, GPLv2\ 2(b) says what terms under which the third parties must

receive this no-charge license.  Namely, they receive it ``under the terms

of this License'', the GPLv2.  When an entity \emph{chooses} to redistribute

work must be GPL and only GPL\@.  In this manner, GPLv2~\S2(b) dovetails nicely

with GPLv2~\S6 (as discussed in Section~\ref{GPLv2s6} of this tutorial).

form, the software serves only the didactic purposes of computer science.

Under copyright law, binary representations of the software are simply

``compilation''\footnote{``Compilation'' in this context refers to the

  automated computing process of converting source code into binaries.  It

  has absolutely nothing to do with the term ``compilation'' in copyright statues.}) to a work of source code yields binary code. The binary

electronic file storage.

Therefore, for GPL'd software to be useful, the GPL, since it governs the

generation of binaries.  Furthermore, notwithstanding the relative

popularity of source-based GNU/Linux distributions like Gentoo, users find

it extremely convenient to receive distribution of binary software.  Such

source code.  GPLv2~\S3 addresses the matter of creation and distribution of

binary versions.

scripts, interface definitions, and other material that is used to

``control compilation and installation'' of the binaries.  In this

manner, those further down the distribution chain are assured that

from the sources provided.

Software distribution comes in many

In contrast, a GPLv2 licensee, under the doctrine of implied patent license, 

is free to practice any patent claims held by the licensor that cover 

``reasonably contemplated uses'' of the GPL'd code, which may very well 

under which the patented code is distributed, expressly permits such activity.

also licenses a Web browsing program under the GPLv2, then it

cannot assert the patent against any party based on that party's use of 

Company \compA{}'s GPL'ed Web browsing software program, or on that party's

party uses that program without

complying with the GPLv2, then Company \compA{} can assert both copyright

infringement claims against the non-GPLv2-compliant party and

infringement of the patent, because the implied patent license only

extends to use of the software in accordance with the GPLv2. Further, if

Company \compB{} distributes a competitive advanced Web browsing program 

program, Company \compA{} is free to assert its patent against any user or

distributor of that product. It is irrelevant whether Company \compB's

program is also distributed under the GPLv2, as Company \compB{} can not grant

\chapter{The Lesser GPL}

As we have seen in our consideration of the GPL, its text is specifically

into the world as possible, particular tactical considerations

regarding software freedom dictate different means. Extending the

copyleft effect as far as copyright law allows is not always the most

Since all applications on a Unix-like system depend on the C library, it

means that they must link with that library to function on the system. In

other words, all applications running on a Unix-like system must be

composed of the original application and the C library. Thus, if glibc

were GPL'd, each and every application distributed for use on GNU/Linux

would also need to be GPL'd, since to even function, such applications

glibc.

At first glance, such an outcome seems like a windfall for Free Software

We strike a difference only in the early portions of the license.

Namely, in the LGPL we go into deeper detail of granting various permissions to

bit more wordy and detailed with regards to the permissions granted to

those who modify or redistribute the software.

cannot modify the primary software program that links to that library.

Finally, the preamble introduces two terms used throughout the license to

the library,'' and ``works based on the library.''  Unlike the GPL, the LGPL must

license because we specifically seek to liberalize the rights afforded to

allows. In the LGPL, we want to draw a line that allows some derivative works

copyright law would otherwise prohibit if the copyright holder exercised

his full permitted controls over the work.

\section{An Application: A Work that Uses the Library}

``works based on the library,'' and ``works that use the library.''  The

of a ``work that uses the library,'' which is set forth in LGPLv2.1~\S5.

We noted in our discussion of GPLv2~\S3 (discussed in

Section~\ref{GPLv2s3} of this document) that binary programs when

the binary is created) or at runtime (when the binary -- including library

and main program both -- is loaded into memory by the user). In GPL,

corresponding source\@.

\newcommand{\workl}{$\mathcal{L}$}

\newcommand{\lplusi}{$\mathcal{L\!\!+\!\!I}$}

\item The new copyright holder, for her software to be useful, realizes

  that it cannot run without combining \worki{} and \workl{}.

  Specifically, when she creates a running binary program, that running

  run.

  the license of \workl{} (the LGPL) can put restrictions on the license

  of \lplusi{}. In fact, this is what the LGPL does.

of a ``work that uses the library'' is for the same reason that GPL has

some say over separate and independent works. Namely, such controls exist

because the {\em binary combination\/} (\lplusi{}) that must be created to

the LGPLv2.1'd software (\workl{}).

Thus, a two-question test that will help indicate if a particular work is

  completely independent work that stands by itself, and includes no

  source code from \workl{}?

  (runtime) linking, to create a new binary work, \lplusi{}?

\end{enumerate}

\section{The Library, and Works Based On It}

In short, a ``work based on the library'' could be defined as any

definition of a ``work that uses the library.''  A ``work based on the

Most typically, one creates a ``work based on the library'' by directly

modifying the source of the library. Such a work could also be created by

tightly integrating new software with the library. The lines are no doubt

fuzzy, just as they are with GPL'd works, since copyright law gives us no

Thus, the test to use when considering whether something is a ``work

based on the library'' is as follows:

\begin{enumerate}

\item Is there no way in which the new work fits the definition of a

  ``work that uses the library''?

In our years of work with the LGPLv2.1, however, we have never seen a work

of software that was not clearly one or the other; the line is quite

dividing the work into smaller subunits. It was soon discovered that

what we actually had were three distinct components: the original

LGPL'd work, a specific set of works that used that library, and a

As we have discussed, the assembly of modules can happen at compile-time

or at runtime. Legally, there is no distinction between the two --- both

mixing them with another. However, under LGPL, there is a case in the

compilation process where the legal implications are different.

are cases where the object code --- that intermediate step between source

from the LGPL'd software.

For efficiency, when a compiler turns source code into object code, it

sometimes places literal portions of the copyrighted library code into the

object code for an otherwise separate independent work. In the normal

linking of the executable occurred. However, when the compiler does this

efficiency optimization, at the intermediate object code step, a

LGPLv2.1~\S5\P4 is designed to handle this specific case. The intent of

the license is clearly that simply compiling software to ``make use'' of

\item Binary distribution of the library only, covered in LGPLv2.1~\S4,

  which is effectively equivalent to LGPLv2.1~\S3

  each other, and distributing them as a unit (in LGPLv2.1~\S7)

\end{itemize}

Software, it is always easy to comply with the GPL. However,

admittedly to the dismay of FSF, many modern and complex software

systems are built using both proprietary and GPL'd components that are

back to the commons that made the work easier in the first place. It is a

reasonable trade-off and a way to help build a better world while also

making a profit.